With the development of various web applications including big data, cloud computing and Internet of Things, there is an increasing demand for a bandwidth of the network communication, especially the demand for a bandwidth of the mobile wireless communication tends to grow explosively. As a new wireless communication method, the FSO (Free Space Optic) communication combines advantages of fiber-optic communication and microwave communication and has a large communication bandwidth, no electromagnetic interference, an unrestricted spectrum and the like. The FSO communication can meet the demand for high-speed wireless communication.
FSO communication is a point-to-point communication in a visual range. In the FSO communication, an emitting end emits an optical signal to a receiving end in a small divergence angle. Only in a case that a lens of the FSO receiving end is in a light spot of the optical signal and an optical power of the received optical signal is sufficient to cause an element such as an optical detector to recover an available data signal, the signal is normally received. Since the FSO communication is generally applied in outdoor wireless communication, and the optical signal is susceptible to factors such as weather and outdoor environment during the optical signal is transmitted in the atmosphere, the optical signal may be significantly attenuated and scattered, which results in a reduced optical power of the optical signal. For example, at the same emission angle and emission power, an effective communication distance of the FSO communication may be up to a few kilometers in a sunny day, while the effective communication distance of the FSO communication may be less than one hundred meters in dense fog.
In the conventional technology, the optical power of the optical signal emitted by the FSO communication system is unchanged. As a result, it is difficult for the FSO communication system to cope with natural environment variation such as the complex weather conditions, and the FSO communication system does not have a capacity of adaptive adjustment, thus the stability of the FSO communication system cannot be ensured.
Therefore, how to provide an FSO communication system which can solve the above technical problems becomes a problem to be solved by those skilled in the art.